Facts & Stats

Upper and lower limb reduction defects occur when a part of or the entire arm (upper limb) or leg (lower limb) of a fetus fails to form completely during pregnancy. The defect is referred to as a “limb reduction” because a limb is reduced from its normal size or is missing.

Limb defects are a diverse collection of conditions, each developing through a different prenatal process, probably with different underlying causes. Proper classification is critical. The most common congenital limb defects can be classified as follows:

* Complete absence of the limb

* Failure of the portion of the limb to separate (commonly seen in fingers or toes)

* Duplication (commonly seen as extra fingers or toes)

* Overgrowth, the limb is much larger than the normal limb

* Undergrowth, the limb is much smaller than the normal limb

* Congenital constriction band syndrome - early rupture of the amnion (inner membranes that cover the fetus in utero and contains the amnionic fluid) resulting in bands that may become entangled in the extremities of the fetus, causing immobilization, constrictions of the limbs, amputations, and other deformities.

Congenital limb defects may also be associated with other bone conditions or syndromes. Always consult your child's physician for a diagnosis.

Although sometimes diagnosed by prenatal ultrasound, there is no systematic screening program for limb defects.

Currently, management of limb defects includes prosthetics (artificial limbs), orthotics (splints or braces) and rehabilitation (physical or occupational therapy). Surgery is often needed in lower limb defects to straighten and stabilize the legs for prosthesis fitting.

The overall goal for treatment of congenital limb defects is to provide the child with a limb that has proper function and appearance.

FACTS & STATS from www.cdc.gov:

CDC estimates that each year about 1,500 babies in the United States are born with upper limb reductions and about 750 are born with lower limb reductions (1). In other words, each year about 4 out of every 10,000 babies will have upper limb reductions and about 2 out of every 10,000 babies will have lower limb reductions. Some of these babies will have both upper and lower limb reduction defects.

Babies and children with limb reduction defects will face various issues and difficulties, but the extent of these will depend on the location and size of the reduction. Some potential difficulties and problems include:

* Difficulties with normal development such as motor skills.

* Needing assistance with daily activities such as self-care.

* Limitations with certain movements, sports, or activities.

* Potential emotional and social issues because of physical appearance.

The cause of limb reduction defects is unknown. However, research has shown that certain behaviors or exposures during pregnancy can increase the risk of having a baby with a limb reduction defect. These include:

* Exposure of the mother to certain chemicals or viruses while she is pregnant

* Exposure of the mother to certain medications

* Possible exposure of the mother to tobacco smoking (although more research is needed)

CDC works with many researchers to study risk factors that can increase the chance of having a baby with limb reduction defects, as well as outcomes of babies with the defect. Following are examples of what this research has found:

*A woman taking multivitamins before she gets pregnant might decrease her risk for having a baby with limb reduction defects, although more research is needed.

*Certain sets of limb reduction defects might be associated with other birth defects, such as heart defects, omphalocele, and gastroschisis.

Currently there is no known way to prevent this type of defect, but mothers can take steps before and during pregnancy to have a healthy pregnancy. Steps include taking a daily multivitamin with folic acid (400 micrograms), not smoking, and not drinking alcohol during pregnancy.